1. Field of the Invention
This invention relates to a high speed image pick-up apparatus arranged to be capable of producing a video signal having a high degree of information density in the direction of the time base of the signal.
2. Description of the Related Art
For the high speed image sensing system of a video camera, it has been known to raise both a vertical scanning frequency fVS and a horizontal scanning frequency fHS at the same rate. However, a method of simply raising these scanning frequencies fVS and fHS necessitates an increase in the frequency band of the signal processing circuit of the camera as the signal frequency likewise becomes higher. Further, in cases where a video signal produced from the camera is to be recorded, such a simple method also necessitates the use of a recording device which has a wide frequency band and is, therefore, very expensive. In the case of a TV signal of the NTSC system, for example, the video signal frequency band is approximately from 0 to 4 MHz. If the processing speed for this signal is to be increased by five times, the camera and the recording device must be arranged to be capable of processing a signal of a frequency band from 0 to 20 MHz.
In accordance with a conceivable method for permitting a recording operation within a lower signal frequency band, the video signal may be divided into a plurality of recording channels. However, the dividing method results in a complex recording signal processing arrangement. Besides, reproduction of the signal recorded in such a manner also requires a complex signal processing arrangement. Therefore, it necessitates use of expensive recording and reproducing systems.
Further, with the signal frequency increased as a whole, in cases where the video signal output of the system is to be displayed by a monitor device, the monitor inevitably becomes expensive as it must be arranged to be capable of operating at a higher speed in response to the increased signal frequency.
Meanwhile, in the field of the home video cameras, video cameras having a high shutter speed of 1/1000 or 1/2000 sec or thereabout have been commercialized. As a result of this, there has arisen a public desire for a video camera and a video recording and/or reproducing system which are capable of producing a video signal having high information density in the direction of time base and yet are inexpensive.
In view of the background described in the foregoing, it is an object of this invention to provide an inexpensive image pick-up apparatus which is capable of performing an image sensing operation at a high speed.
It is another object of the invention to provide a high speed image sensing system which permits use of inexpensive recording/reproducing apparatuses.
Under the above stated object, an image pick-up apparatus which is arranged according to this invention comprises: image sensing means for converting an image of an object formed on an image sensing plane into an electrical video signal; synchronizing signal adding means for adding horizontal and vertical synchronizing signals to the video signal produced from the image sensing means; periodic signal generating means for generating a periodic signal of a frequency which is an n number (n: an integer which is at least 2) times as high as the frequency of the vertical synchronizing signal; and scanning signal generating means for generating and supplying to the image sensing means a vertical scanning signal to cause a vertical scanning process to be performed on the image sensing plane in a cycle which is 1/n of the period of the vertical synchronizing signal on the basis of the periodic signal.
The above and other objects and features of the invention will become apparent from the following detailed description of embodiments thereof taken in connection with the accompanying drawings.